It may be the riskiest thing you do, and if you're like most people, you do it every day: get in your car, get on the road and take your chances.

To identify the most dangerous roads in America, Dateline analyzed five years of federal crash data. We added up the fatalities, county by county, road by road, during that period. Of course roads vary by how long and how busy they are, but for our survey we decided to stick to total fatalities. We found roads with high numbers of deaths, then we visited those deadly roads, some of them near you.

We'll start our survey not in a car, but trying to avoid them -- on roads that are most dangerous to people on foot. Pedestrian fatalities account for about 10 percent of all traffic deaths, and each one shatters someone's family.

It was a muggy august night in the town of New Port Richey, North of Tampa. Billy Uhle and his mom, Nanette, discussed whether he would sleep over at a friend's house or walk home. About 1 a.m., Billy decided to walk. He was a mile from his house, on the side of the road. For reasons no one knows, a car veered right.

It's a sight both horrible and common when a car hits a pedestrian at high speed. Shoes rooted to the pavement, the victim is tossed down the road like a rag doll. Billy's Uhle's body was found 25 feet from the point of impact.

Billy wasn't drunk, wasn't doing anything reckless, wasn't doing anything careless. He was just walking along the edge of the road. That was enough.

Take one family's grief and multiply it by 100. That's how many pedestrians have been hit and killed on Florida's US-19 in five years. It's a six-lane meat grinder running 30 miles up Florida's Gulf Coast. We first visited in 2002, and found the shoulders of the road dotted with white crosses memorializing the dead. With fatalities in triple figures, US-19 is at the top of our list of dangerous roads.

Sgt. Erik Anthes: “It's depressing because you see the carnage that goes on out there.”

Sgt. Anthes has driven US-19 since he learned to drive. Now he's in charge of the Pasco County Sheriff's Department Traffic Safety Program. He showed us how miles go by without a sidewalk, forcing pedestrians to walk the often muddy shoulder or take their chances on the pavement. And when night fell, we saw long stretches of road without streetlights, making pedestrians all but invisible to speeding drivers.

US-19 may be the most dangerous road in America for pedestrians who have to cross it or walk along it, but it has plenty of company. In our review of five years of federal crash data, we found roads from coast to coast with no sidewalks, unsafe crossings, speeding traffic and some roads that are dangerous just because of where they are. The lesson here is pretty clear. In a land where the car is king, the person on foot better get out of the way.

Dan Burden: “All of those roads were built without any consideration for the pedestrian. They weren't an afterthought. They just weren't a thought at all.”

Dan Burden is what you might call a professional pedestrian. He used to be a safety coordinator for the state of Florida. Now he literally walks the country as a pedestrian safety consultant and advocate. Burden says unsafe walking conditions hit poor people the hardest.

That seems to be the case in Dallas, where Interstate 30 cuts right through town. There the highway separates low cost motels and apartments on one side from discount stores on the other. When residents, many without cars, have to shop for groceries, some make the fateful decision to run across 10 lanes of 60 mile an hour traffic. Over five years, 33 pedestrians died on this highway, putting I-30 on our list of dangerous roads.

Dallas traffic safety officer Debra Guajardo-Raffety gives safety classes for recent immigrants, who suffer a disproportionate number of pedestrian fatalities in Dallas. She teaches a key rule of the road, that while a relatively small percentage of pedestrian crashes happen on interstates, virtually every one of them is fatal.

It may seem like common sense not to run across a freeway, but what about a city street that resembles a freeway? In Arizona's fast-growing Maricopa County, Indian School Road cuts across Phoenix. It's wide, and it's fast. Over 5 years, 27 pedestrians have died there, putting Indian School on our list of most dangerous roads.

Speed also kills on the fabled route 66, named Foothill Boulevard as it passes through San Bernardino County in Southern California. Twenty-five pedestrians were killed here over five years, putting this road on our most dangerous list. It's not hard to see why. The speed limit is 55, and, on one section near the city of Fontana, there's an astounding two miles between traffic signals. But it's not just crossing that's dangerous. Often the lack of sidewalks forces people to walk in the road with the speeding cars.

It's not just these roads. Cities across the country have roads just like them.

But there's a road that proves it's possible to get off the most dangerous list. In the New York City borough of Queens, you'll find Queens Boulevard. In 2001 the Daily News dubbed this the "Boulevard of Death.” Pedestrians were being killed at the rate of one every six weeks. Since then, the city has put up warning signs, re-timed traffic lights, and built fences to discourage jaywalkers. Pedestrian deaths have declined sharply. The city says there was just one last year.

And even the most deadly roads can be improved. Remember US-19, the worst road in the country? Well, here's a surprise -- it's getting better, in large part because a county commissioner named Karen Seel decided she had seen enough white crosses. Seel formed a task force to figure out how to fix US-19. Then she proceeded to twist arms at the state legislature and at local businesses alike to raise the money required, $350 million dollars in just her county, Pinellas.

The results benefit both motorists and pedestrians. There are more sidewalks, highly visible signs that let drivers focus on the road, and even new overpasses at major intersections to decrease traffic conflicts. Up the road, in Pasco County, where Billy Uhle was killed in the dark of night, brand new streetlights are about to be turned on. It's too soon to know how many lives these changes might save, but Warren and Nanette Uhle, who lost their only son, say that even one life is enough.

They roll across the high desert of California, the mountains of Montana and the Carolina low country, highways millions of Americans drive every day. From US-1 in the Florida Keys, to Central Pennsylvania's State Road 41, and all the way across the Pacific to Hawaii's State Road 19, we know them when we drive them -- roads that turn your knuckles white, as you wonder whether that 18-wheeler is going to stay on his side of the yellow line.

They are the mostly rural, often two-lane highways that carry only 28 percent of the nation's vehicles but are responsible for more than half the fatal accidents.

Gerald Donaldson works at the Advocates for Highway and Auto Safety, a consumer and insurance industry supported group.

Josh Mankiewicz: “What makes these roads so dangerous?”

Gerald Donaldson: “They have severe curves so that they have poor sight distance. They have narrow lanes, and all you have to do is just to depart that lane a couple of feet and you're into an extremely hostile territory. There is no margin for error on those roads."

To determine where these dangerous roads are, Dateline searched a federal database listing nearly every fatal traffic accident in the country. There are 400,000 miles of two lane highways in the United States, many with a disproportionate share of accidents. On State Road 138 in Southern California, head on collisions, overturned vehicles and cars going off the road are common. But despite that, many drivers don't realize just how dangerous two lane highways like this can be. There are places where an inattentive moment can be your last. Though 138's image has been helped a little by calling it the Pearblossom Highway, to locals it's the deathtrap highway or just blood alley.

State Road 138 spans two California counties, and, with 22 fatal accidents in Los Angeles County and 17 in San Bernardino County in a five year period it easily made our list of dangerous roads. L.A. County firemen Ron McFadden and Jeff Britton have seen firsthand how many ways people can die on this road. The firemen have even had to pull drivers -- dead and alive -- from the California aqueduct that runs near the Pearblossom.

Roads like 138 tell the story of America's cities. They began as rural farm-to-market roads, but when urban sprawl caught up with them, they began to carry more and bigger vehicles than they were designed for.

Donaldson says that more trucks and SUVs equals bigger and worse accidents. Add in factors like speeding and drunk driving, as well as the failure to use seatbelts, and these inherently dangerous roads just take more and more lives.

To really get a feel for the risks these roads carry with them, drive US-2 in Montana from the Idaho border down to Kalispell. It's high speed, mountain driving, with steep grades and dangerous turns, and that's why it made our list. We drove it with Larry Strokland of the Libby, Montana American Legion. He knows this road better than most. For 50 years Legion members like Strokland have been putting up metal crosses marking Montana highway fatalities. Strokland says it's a safety program. They hope it wakes up drivers and makes them think to use caution.

And if you drive 2,700 miles southeast to US-17 in South Carolina you can hear a similar story. US-17 is a high fatality road running nearly the length of the state. The unforgiving nature of this two lane stretch in Beaufort County added it to the dangerous road list. The dangers of US-17 were well known to Dana Gasque. In January 2004, her son, Cooper, was driving back to college on US-17 when his car collided with one driven by Sherry Leeks' 20-year-old daughter, Kassandra. In that instant, two young lives were lost and two families forever changed.

Four weeks after that accident, three sailors died in a crash just up the road on 17, and more fatalities would follow.

Rather than trying to assign blame for the accident, these two families have dedicated themselves to getting the road fixed so others don't suffer as they have:

What can be done about these roads? They need the kind of improvements that are planned for literally every highway in this report: safety upgrades like center median dividers, additional travel lanes, wider shoulders and rumble strips. But the problem is money. According to experts like Donaldson, too much federal money went for too long to the Interstate system and not enough to upgrade and maintain smaller, more dangerous, routes.

If you drive anywhere in America, you've noticed that the nation's roadways are crowded with drivers who see the speed limit not as a law, but as a suggestion. We've all developed a bad habit, and a dangerous one: speeding. It's killing thousands of people each year, and it's no accident.

Mankiewicz: ”You don't like the word accident.”

Richard Retting: “An accident suggests that there was no way to anticipate the event and prevent it from occurring. Crashes are anticipated, and therefore they're preventable.”

Richard Retting is a senior transportation engineer at the Insurance Institute for Highway Safety, a nonprofit research group funded by auto insurers. He says that, behind the wheel, we're a nation of law-breakers.

Retting: “On many roads, I suspect drivers don't even know what the speed limit is because they don't pay attention to speed limits.“

Speeding contributes to nearly one-third of the nation's traffic fatalities, and on roads where drivers routinely speed, the risk is high, and deadly.

To find those dangerous roadways, Dateline analyzed five years of the most recent federal data, county by county, to identify roads with high numbers of fatal crashes involving speeding drivers, crashes where police reported both the posted speed limit and how fast the driver was going. We looked at two types of roads, beginning with high-speed highways. All had a posted speed limit of 55 miles per hour or higher.

First on our list is stretch of Interstate 15 in the desert that runs from Southern California to the Nevada line. Each year, millions of visitors speed along this road, seeking their fortune in Las Vegas. Some never make it. Over five years, speeding cost 173 people their lives there, putting Interstate 15 at the top of our list of dangerous high speed roads.

Other dangerous sections of I-15 run through Nevada and Utah. And in the southeast, Interstate 95 is a heavily traveled freeway with high numbers of fatal crashes in counties stretching from North Carolina to Florida. That's where we met the Schaefer family. Kathy Schaefer admits she was overprotective of Casey, her only child. It was up to Kathy, and her husband John, Casey's stepfather, to keep Casey safe. And she was safe, until one summer night in 2003. The 16-year-old Casey went to the movies with friends.

Kathy Schaefer: “It was a little before 11 and there was a knock on the door. My first thought was Casey forgot her key. And it was not Casey at the door, it was a police officer.”

Casey had been in a car wreck.

Schaefer: “When I got to the hospital, security immediately ushered me in to a private room, where I was met by the attending doctor. The doctor immediately offered me some form of tranquilizer pill to calm me down. I just said I don't need any pills, I just want to see my daughter. And that's when she said we did everything we possibly could but she did not make it.”

Casey and another girl died when the SUV they were riding in rolled five times. The teenage driver was a friend of Casey's. He was driving at least 10 miles over the 65-mile-an-hour speed limit on Interstate 95.

The deadliest stretch of I-95 on our survey is in Palm Beach County. From Boca Raton up to Jupiter, speed killed 48 people, putting this Interstate on our list of dangerous roads.

Trooper Paul Rich: “When planes take off, they take off at about 150 mph. These people are running at 120, 130 miles an hour out here. They're about ready to take off”

Riding with Florida highway patrol trooper Paul Rich, we witnessed some typical I-95 speeds. The speed limit there ranges from 55 to 65. One driver is stopped for driving 86 miles an hour, as is a second driver. Another driver is caught on a radar gun at 96 miles an hour. That doesn't stop him from trying to talk his way out of the ticket.

But Interstates aren't the only roadways with speeding problems. We also looked at roads with posted limits of 45 miles an hour or less. Drivers may not go as fast on these streets as they do on Interstates, but the effects are still deadly.

In Clark County, Nevada, Sahara Avenue is a typical Las Vegas street. It carries traffic from one end of this fast-growing city to the other. Take away a few intersections and it could be a highway -- which is just how people drive it. With 14 deaths from speeding-related crashes, Sahara made our list of dangerous roads.

We found more wide roads in Maricopa County, Arizona, another region with record population growth. In our survey, seven of the 10 roads with the highest number of fatal speeding-related crashes in the nation are there, crisscrossing Phoenix, the county's largest city. In five years, 190 people have been killed on these streets, putting all seven on our list of dangerous roads.

Phoenix Mayor Phil Gordon: “Unfortunately, because of the way the roads are, they're wide, the weather is clear almost the whole year, and there's no curves or turns in it, people speed.”

He says Phoenix is actively working with neighboring cities in Maricopa County to bring down drivers' speeds. But speeding isn't isolated in the West. Some of the other roads on our list include sections of US-92 through Tampa, Fla., US-1 through Raleigh, N.C., and US-40 through Denver.

Since the national speed limit was abolished in 1995, speed limits -- and drivers' speeds -- have been on the rise around the country. Traffic expert Richard Retting says the consequences are tragically predictable.

Nearly 17,000 people are killed each year not because the road's too narrow, not even because they're speeding, but because someone decided to drive after drinking. Dona Rose was neither a drinker nor a driver, but 25 years ago, a drunk driver changed her life forever.

Dona Rose: “I went through the windshield and suffered a severe head injury and was in a coma for six months and not expected to recover.”

She eventually woke up from her coma, but at age 25, Dona had to re-learn everything: how to walk, how to eat. Much of her memory, her past, was lost. It was as if she were a child again.

Mankiewicz: “When you're that age you don't think too much about the future. But back then, what did you want to do with your life?”

Rose: “Probably marry you.”

I was thinking the same thing 40-some years ago. Dona Rose and I were nursery school sweethearts. Our lives went in different directions. She had wanted to be a ballerina. In college, she was a nationally-ranked gymnast. But today, even walking is a challenge. Dona's now lived half her life that way.

Mankiewicz: “That's all from the accident?

Rose: “Yeah… I'm really embarrassed about my lack of balance. My speech I think I can hide that a lot. Everything takes me longer than it might take you.”

As part of her therapy, Dona has become a very strong swimmer. But her path to recovery wasn't easy. At the time of her accident, Dona was engaged, but she says she pushed her fiancé away, because of her own depression.

Rose: “I really wanted somebody to kill me. Or I wanted to kill myself, but I couldn't think of any way to do that.”

Jim Gogek: “Drunken driving injuries and fatalities are a tragedy. We seem to as a nation to have forgotten this.”

Jim Gogek is with the Pacific Institute for Research and Evaluation, which has published studies on alcohol-related driving fatalities. The DUI death toll used to be as high as 30,000 per year before mandatory seatbelt laws were adopted in the 90s. But there has been little improvement since then, with annual DUI deaths stagnating at nearly 17,000. That's about 40 percent of all traffic deaths in the nation.

Our review of five years of federal crash data identified roads where you're likely to encounter a drunk driver. That search took us back for the third time to Maricopa County, Ariz. Three of its streets run through the fast-growing city of Phoenix. Broadway, Thomas and Indian School Roads are all on our list of dangerous roads.

Sgt. Joel Tranter is with the Phoenix police DUI unit. We joined him one night, as he searched for signs of impaired driving. It didn't take long.

Joel Tranter: “He's squealing his tires. He's splitting that lane right there. He's tailgating. He's driving reckless. He's putting other people in a hazard out here.”

Sgt. Tranter stops and arrests the suspect, whom he says has a blood alcohol content of .172. That's more than twice Arizona's legal limit, which is .08. About an hour later, this suspect is struggling to walk a straight line and count his steps. His breath test may explain why. Police say it's .24.

And it's not hard to see why these streets attract so many drunk drivers, once you check out the number of bars and liquor stores.

But across the country, most drunk-driving fatalities occur on the freeways, because of the high volume of traffic and the high speeds. That's how busy interstates made our list, such as Palm Beach County Florida's I-95, the Harris County, Texas stretch of I-10, and the Cook County, Illinois section of I-94. But the San Diego County, California portion of I-5 is first on our list of dangerous roads.

Each year, 10,000 to 15,000 people are arrested for driving under the influence in San Diego County, an average of almost 35 a day. We rode with the California Highway Patrol for one night and saw 6 DUI arrests. Just why is I-5 so dangerous? One reason is that it ends in Tijuana, a Mecca for bar hopping and partying. To drink in the U.S., you have to be 21, but in Mexico you only need to be 18.

While there, we asked people before they headed home, to volunteer for a breath test. We brought along Keith Nothacker, a distributor of breathalyzers, to properly apply the tests. Most people walked right past me. If they were drunk, they apparently didn't want to know how just how drunk.

We also met a group of 18 and 19-year-old college students, who agreed to let us follow them on their night out in Tijuana.

Mankiewicz: “Am I right in thinking that the reason you guys come down here is because you can drink here when you're 18 and in the United States you have to wait until you're 21?”

Jack: “I'll agree.”

Jordan: “Yeah, there's really no other reason to be down here except to party.”

And party they did, until about 4 a.m. Along the way we learn that one guy is the designated driver. But is he sober?

Mankiewicz: “How much have you had to drink?”

Jack: “I'd put it between somewhere between 18 and 23.”

Mankiewicz: “18 to 23 shots?”

Jack: “Twenty-three actual beers… shots.”

It's time to put the breathalyzer to work.

Mankiewicz: “You are legally drunk.”

Jack: “Oh, real-- thank you.”

He thinks it's funny, but he's almost double the legal limit. A common belief is that you can tell if you're too drunk to drive, but experts say that's not true. You can become impaired after just one drink. We test another one of the college kids, Jordan.

At .05, he's under the legal limit, and they decide to let Jordan drive home. All four promised us that they'd sleep in the car for a couple of hours before hitting the highway -- but 10 minutes later, they were on the road.

Jim Gogek: “Most of the laws that we need are already in place. These are real lives. One of the problems is we used to know this. But now we've become complacent about this. “

My friend Dona Rose is fighting that complacency. She now speaks to students about her experience, how one person's decision to drive drunk took away so much of her life. The ripples from that accident spread a long way, affecting more than just her balance or memory. Her depression lifted, but she never married or had children. Her dreams evaporated in the instant of that collision. But that trauma also gave Dona's life a purpose.

Rose: “It's really the only thing I can do, I think. And because I get such feedback, and I do it well.”

Mankiewicz: “You think you've saved lives?”

Rose: “I hope so… And I don't ask them not to drink. I just tell my story. And they said they won't ever drink and drive.”

We've seen killer roads all across this country, but every day, most of us don't face sudden death. Instead, we battle that slow, painful, daily descent into madness -- also known as traffic.

Across this great nation gridlock is an epidemic, and the citizens of America are suffering. Yes, it's getting worse where you live. How do I know that? Because it's worse almost everywhere. Traffic congestion across the country has nearly tripled in the last 20 years. There are more cars on the road each day than the day before and those cars are bigger than ever before.

Freeways everywhere are at full capacity, and in most cities, like L.A., there's no room to expand them. If anything out of the ordinary happens on these already cramped highways, like construction, bad weather, a broccoli truck rolls over, a normal backup turns into a dead stop for miles.

Doug Failing runs the freeways in Los Angeles.

Mankiewicz: “You think you're doing a good job?”

Doug Failing: “I think we're doing a very good job with what we've got available.”

Like a lot of other cities, L.A. has a high tech command center that monitors the freeways and puts out bulletins to help drivers avoid jams. Most on-ramps there are metered to smooth the traffic flow. L.A. also uses a fleet of roving tow trucks to clear stalled vehicles and wrecks quickly and for free. They are good ideas, but they really just keep traffic from getting even worse.

Mankiewicz: “Is it ever going to get better?”

Failing: “No. No it's not.”

Every year, the traffic team at the Texas Transportation Institute rank U.S. cities on the severity of their congestion, how many extra hours each commuter spends each year sitting in traffic. This year's winners are: Houston with an annual 63-hour delay per commuter, Atlanta with a 67-hour delay, D.C. with a 69-hours, and number two, the San Francisco Bay area, with an annual delay of 72 hours.

Who's number one? Los Angeles, with a whopping 93-hour traffic delay each year. For each traveler. That's almost four days spent staring at someone else's bumper. It turns out a big part of the problem is drivers like me who don't use mass transit, and who don't carpool. In a lot of places, mass transit won't work because it's too expensive to build and cities are now too spread out. And as for carpooling, the simple fact is most people won't do it.

There is actually a traffic solution designed with the loner in mind: so-called Hot Lanes, where single drivers can get into the carpool lane by paying a special toll. Unfortunately, there are only five of those in the United States right now .

One piece of advice from experts is to try being a courteous driver for a change. Chronically changing lanes and braking for billboards create major shockwaves, so being nicer makes traffic flow faster. So i'll work on my manners. It's not as if I don't have time.

Dateline wires the home of a volunteer, Jenny, from top to bottom with hidden cameras. Then she called repairmen to her house for a simple problem we created as a test with Jenny's pool. NBC's Chris Hansen reports.